Apparatus for closing and clamping split rings about alpha mandrel



E. A. KOETHER April 5, 1932.

APPARATUS FOR CLOSING AND CLAMPING SPLIT RINGS ABOUT A MANDREL Filed April 7, 1930 5 Sheets-Sheet l April 5, 1932.

E- A. KOETHER APPARATUS FOR CLQSING AND CLAMPING SPLIT RINGS ABOUT A MANDREL Filed April 7, 19,30

eats-Sheet 2 dual/wa t April 5, 1932. E. A. KOETHER 1,352,529

APPARATUS FOR CLOSING AND GLAMPING SPLIT RINGS ABOUT A MANDREL Filed April 7, 1950 5 Sheets-Sheet 3 y lmwmp Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE EMIL A. KOE'I'HER, OF BALTIMORE,MAEYLA1\TD, ASSIGNOR TO THE AMERICAN HAM- MERED PISTON RING COMPANY, 01- BALTIMORE,

MARYLAND MARYLAND, A CORPORATION OF APPARATUS FOR CLOSING. LAND CLAMPING- SPLIT RINGS ABOUT A MANDREL Application filed Aprili7, 1930. Serial No. 442,352.

This invention pertains to means for securing split rings on mandrels. More specifically it pertains to means whereby a plurality of split piston rings or blanks are closed 1 about a mandrel along with means for maintrated in the annexed drawings wherein:

Figure 1 is a perspective view of the apparatus in its open position ready to receive a. mandrel and the rings mounted thereon,

Figure 2 aside elevation of a mandrel with a series of rings mounted thereon,

Figure 3 a longitudinal sectional view with a series of rings and a mandrel in place and the parts brought to pressure exerting position,

Figure i a transverse vertical sectional view with the parts in the same relation,

Figure 5 an end elevation of the structure and the associated power mechanism, and

Figure 6 a side elevation of the mechanism with the parts separated.

In said drawings 1 denotes the base of the structure formed frommetal and preferably clamped upon a supporting frame-work 2. Said base, as will best be seen upon refer ence to Figures 1, l and 5, is provided with a semi-circular recess or concavity in its upper face. Formed in said face and extending longitudinally thereof is a plurality of channels 3, three of such channels being shown, one located at the center of the base and the other two equidistantly spaced therefrom. In each of the channels is mounted a pressure bar or shoe taking against a resilient pressure element 5 preferably formed of rubber.

To prevent the members 5 from being displaced I preferably hold them in position by plates 6 and 7 which engage the periphery of the same and have the edges thereof which engage the periphery inclined. In other words the diameter of the pressure element 5 is greater than the space between the adjacent edges of the members 6 and 7although the members 5 maybe forced outwardly be tween said plates to properly position the same by a series of screws designated generally by 8. The pressure elements 5 are designed to take against the periphe of the rings to be positioned upon an ar or, the rings being denoted by9.

Cooperating with the base lisa head 10 also formed of metal. and, as is the case with the base 1, sufliciently heavy so as not to yield under pressure. Said head is provided on its under face with a semi-circular concavity formed upon the same radius as that of the lower concaved surface. The head 10 isprovided with two elongated slots 11 in which are mounted pressure bars or shoes 12 which extend substantially throughout the length of the head, said bars taking against yielding pressure exerting elements 13 similar to the members 5 in the base. Said members 13 are of the form of the members 5 and are held in place by similar plates 6 and 7. Adjusting screws 8 are employed in conjunction with the bars 12 as is the case with the bars heretofore referred to.

To prevent displacement of the head 10 as it is moved up and down guide rods 14 and 15 are employed and in order to secure. absolute register of the head with the base as the parts come together guide dowel pins 16 are utilized. Said pins are fixed inthe base land are designed to enter openingsformed in the head 10 when the parts arebrought'to'their final pressing position.

In order to raise and lower the head, and to apply pressure as the head comes to'its closed position any suitable power mechanism may be employed.

In Figure 5 the head is shown as beingsupported by a stem 17 mounted for reciprocation in the overhanging portion 2 of the supporting frame. To the upper end of this stem there is secured a lever 18 fulcrumed upon arocking link 19 mounted upon the overhanging arm 2 The rear end of the lever 18 is connected to the piston rod 20 which works in apower cylinder 21. Ingress and egress of air or other fiuid is controlled through manipulation of a handle 22 operating a valve 23.

Preferably a mandrel of the form best shown in Figures 3 and 4 will be employed. It consists of a centrally disposed bar 24 which at one end is somewhat enlarged and shouldered as at 25 against which bears a collar or ring 26. Said ring is secured to the rod or bar 24 against rotation with reference thereto by pins 27 d 'iven into the bar and taking in a guideway 28 formed within the ring. The outer end of the bar at that end adjacent ring 26 is formed with exterior fiat faces 29 which bear against faces 30 formed in a bracket 31 supported upon bolts 32 secured in the adjacent end of base 1. WVhen the mandrel is positioned this engagement of the parts prevents rotation of the mandrel and possible displacement of the rings which might otherwise take place when the ring blanks are locked in position on the mandrel.

As will be seen upon reference to Figure 3, the inner end of collar 25 is reduced in diameter exteriorly and fitting over such reduced end is a tubular member 33 which forms the ring supporting element of the mandrel. A collar 34 surrounds the adjacent end of said member 33 and the parts are secured together by a pin 35. Furthermore the parts are so proportioned as to produce a driving fit.

Adjacent the opposite end of the bar 24 there is placed a ring 36, said ring tightly fitting the bar and likewise taking against the inner face of the tubular member 33 which it supports at that end. Outwardly of the ring and abutting the end of the tubular member is a washer 37.

I Overlying the end of the tubular member 33 and the ring 37 is a pressure applying ring or collar 38. Outwardly of said ring or collar 38 and the ring 37 is a pressure applying Washer 39, said washer being held against rotative movement by a pin 40 secured in the ring 37 and moving freely in an opening formed in the washer 39. A nut 41 is mounted. upon the outer threaded end of the member 24 and, as will be appreciated, by turning the same up, the member 39 will be forced against the collar 38 and the latter will in turn be moved longitudinally of the member 33. Prior, however, to this operation a series of rings 9 is mounted upon the tubular member 33 with washers 42 interposed betweenv the same. A plurality of such washers are first mounted on the member 33, as best shown in Figure 2, and a similar arrangement is effected at the opposite end.

It is to be noted that the flexible pressure applying elements 5 and the similar parts extend beyond the inner ends of the collars 26 and 38 respectively. The advantage and purpose of this will presently appear.

hen a mandrel has been loaded with rings and washers in the manner shown in Figure 3 it will be placed in the lower portion of the structure with the rings coming to rest upon the members 5. At such time the squared portion 29 contacts the faces 30 and the mandrel is thus locked against rotation. The head or other element 10 is then lowered bringing the upper flexible members 13 into contact with the rings and, as pressure is applied the rings will be closed. Preferably, in order to secure uniformity in production, the joints or openings in the rings will all be brought to a common position, preferably with the joints uppermost. This may be effected by the use of a thin bar which is temporarily inserted in the joints. A thin strip of metal backed with rubber is then preferably placed over the joints prior to the closing of the head 10. Then when the parts are brought together by the application of aheavy wrench upon the nut 41 the washer 39 and the collar 38 are forced endwise placing the various rings and washers under compression and so tightly locked that they cannot move until the nut is backed off. With the ring blanks 9 thus closed and positioned about the mandrel the head 10 may be raised and the mandrel, with the rings thereon, removed. The mandrel, which is provided with deep centers as 43 and 44 at its respective ends may then be placed in a lathe and the rings turned.

By the use of the present apparatus various requirements as to ring specifications may be met. 7 During the past few years the specifications for piston rings have become much more rigid and certain requirements are now essential which were not a few years back. For instance, the circularity of a ring is now one of the most important specifications and is almost always specified. By circularity is meant the roundness of a ring when compressed in a flexible band until the oints are closed. The roun dness is then measured by means of micrometers or other suitable measuring devices. The roundness or circularity is generally expressed as being plus or minus, depending upon whether the ring is of a greater diameter on the axis extending through the joint than with the axis perpendicular to the joint. The specifications for circularity vary so much on account of the ideas of the different manufacturers that it is impossible to make rings of any one diameter to the same circularity and comply with all manufacturers requirements. On rings from 3 to 4' some manufacturers specify the circularity shall be from plus .005 to plus .015 7 whereas others specify circularity from zero to .010" and still others specify the circularity shall be within .005"that is, plus or minus .005.

- The structure above described provides a simple and accurate mechanism whereby rings conforming to any and all requirements may be readily effected.

Various means of manufacturing rings to- .j

the proper circularity have been tried in the past such as cam turning orforcing ring castings of special 11on-circu1ar form while unsplit over an arbor of predetermined form and then turning so that the rings will spring to the required form when removed from the arbor, and also by various means of heat treating. However, the most common method at present is to cut a piece from the circumference of the ring that has been cast to apredetermined form andthen close the ring by means of a flexible wire or string Wrapped around the circumference and pulled tight and while held in this position by means of pins or side pressure, turn to size on a lathe. This method, however, produces rings of approximately zero cir cularity and, in VlGW of the fact that the ends of a ring are its weakest points such a ring will invariably cause a blowby in a motor and therefore will soon fail. In oruer that the proper pressure at the oints may be maintained when the ring is in operation, it is essential to be able to produce rings with. varying circularity depending upon the use for which they are to be put.

The operation of the device described herein will now be set forth. Castings are produeed in the foundry to a definite shape similar to an ellipse so that when a piece is cut from the circumference of the casting and the casting closed by means of a flexible band it will then be approximately round. These castings are face finished on the sides so that the faces are flatand parallel. Next the joints are cut, after which the rings are placed on the arbor of a certain definite size so that there is a slight clearance between the arbor and the inside of the rings when the joints are closed, in order to allow for any incoualities on the inside of the castings. My means of the rubber cores or hearing strips extending longitudinally through the box, the inequalities of the castings are taken up and a. fairly uniform pressure is exerted on each ring. Also the joints in all rings are brought together; therefore, when turned all rings will be of the same diameter and have the same end clearance or gap opening when placed in the same cylinder. This is a most important point to emphasize as the specifications for end clearance are extremely rigid at the present time and only by means of some such structure. as herein described could the joints of all rings be closed, thus producing rings with the same dimensions.

By the use of the present apparatus rings oi any required circularity may be easily produced. By the use of the rubber cores or hearing strips backed up by shoes, which may be adjusted by the screws, the rubber cores or strips can be moved in and out radially toward the axis of the core box so that the rings can be pressed to any desired form when the box or press is closed. For

instance, if it is desired to make a ring with a plus circularity extra pressureis applied from the bottom rubber core by tightening up on the adjusting screws and when rings are placed in the core box and the two halves are brought together therings on the arbor are all pressed to a minus circularity and then clamped in this position by means of th nut 41. While in this position they are turner. circular to the required diameter and then when the nut 41 on the arbor is unscrewed and the rings are released, it will be found that every ring when compressed in a flexible'band will have a plus circularity.

By means of the live rubber lands or strips such a flexible closing device iscapableof producing rings on a production basiswith almost any degree of circularity specified. The only thing necessary is for the adjuster in charge to determine by experiment the proper amount of pressure to put on any one land. The adjusting screws arethen looked in this position and the core box placed in operation where unskilled labor cannot fail to produce rings of the required circularity and all exactly alike.

It is essential to have the collars onithe arbor, one at each end and bearing against the rings. The rubber cores press against the rings as well as the collars andlthus centralize the rings and the collars with reference to oneanother. The collars fitthe arbor very neatly so that the rings are thus centralized with reference to the axis of the arbor and the lathe centers so thatwhen the rings are turned on the lathe the arbor will run concentric and approximatelythe same amount of metal will be removed from all points of the rings.

It is to be understood that the term split ring as employed herein includes any type of joint or split formed in the ring. It is also to be noted that in Figure 3 and Figure 4 the members 1 and 10 have not been fully closed and that the rings 9 are not, therefore, shown in contact with the body of the member 33 nor are the ends of the rings shown as in contact.

What is claimed is:

1. In an apparatus for closing, controlling the circularity of, and clamping split rings about a mandrel, the combination of a mandrel; means for closing the rings about the same; means for exerting variable pressures at a plurality of points about the mandrel; and means for clamping the closed rings together in a facewise direction.

2. in an apparatus for closing and positioning split rings upon a mandrel;the combination of a mandrel; a plurality of pressure exerting elements spaced about the mandrel and extending longitudinally thereof; at least two yielding members extending inwardly from the inner face of each of said pressure exerting elements; and means for adjusting said yielding members with reference to the inner face of the pressure exerting elements.

3. In an apparatus for closing and clamping split rings upon a mandrel, the combination of a mandrel; a plurality of yielding elements movable toward the mandrel and into contact with the outer face of the rings to be closed; means for forcing said elements inwardly toward the axis of the mandrel;

means for securing adjustment of said yielding means with reference to said forcing means; and means for clamping the closed rings together in a facewise direction.

4. In an apparatus for closing split rings upon a mandrel, the combination of such mandrel; two opposed members each having a concavity in line with the mandrel; a plurality of resilient elements carried by each of said members, said elements extending lengthwise of the members and projecting outwardly beyond the wall defining the concavity; means for securing adjustment of said resilient elements with reference to the face of the wall; and means for moving the members toward each other and thereby causing the resilient elements to contact the rings and force the same into contact with the mandrel.

5. An apparatus as set forth in claim 4: provided with means for clamping the rings in a facewise direction.

6. An apparatus as set forth in claim l wherein the resilient elements are bodily adjustable toward and from the aXis of the mandrel.

7. An apparatus as set forth in claim 4 wherein the resilient elements are independently adjustable toward and from the axis of the mandrel.

8. An apparatus for closing split rings upon a mandrel, the combination of a mandrel a member presenting three points of contact for the rings mounted on the mandrel; a second member presenting two points of contact, said latter points being so located as to contact the rings upon opposite sides of the split thereof; and means for forcing said members toward each other.

9. An apparatus for closing split rings upon a mandrel, the combination of a mandrel; a member presenting three yielding points of contact for the rings mounted on the mandrel; means for securing adjustment of said contact points toward and from the mandrel; a second member presenting two yielding points of contact, said latter points being so located as to contact the rings upon opposite sides of the splits therein; ant. means for forcing said members toward each other.

10. In an apparatus for closing split rings upon a mandrel, the combination of a man drel; a member provided with a concavity extending longitudinally of one face thereof;

a plurality of resilient elements carried by the member and extending outwardly beyond the wall of the concavity; means for adjusting said elements to produce a greater or less protrusion thereof with reference to the face just mentioned; a second member provided with a concavity in that face adjacent the concavity aforesaid; a plurality of resilient elements carried by said member extending inwardly of the wall of the concavity therein; and means for forcing the members having the concave faces therein toward each other and toward the mandrel.

11. In a mechanism for closing split piston rings upon a mandrel and clamping the same in facewise relation, the combination of a member having a concavity formed therein and extending longitudinally thereof; a plurality of resilient elements extending longitudinally of said member and projecting into the concavity; a second member movable toward and from the first named member, said second member having a concavity formed in that face opposite the concavity formed in the first member, said concavity likewise extending longitudinally of said member; a plurality of resilient elements carried by said second member and extending inwardly of the wall of the concavity therein; a mandrel extending lengthwise of said members and positioned within said concavities; a collar fixed at one end of the mandrel, said collar taking against the resilient element aforesaid; a second collar mounted upon the opposite end of the mandrel and likewise taking against the resilient elements; means for forcing the con cave members toward each other to close the rings upon the mandrel; and means associated with the second named collar for forcing the rings into clamping relation with each other.

12. A structure as set forth in claim 11 wherein means is provided for preventing rotation of the mandrel.

13. In a mechanism forclosing and clamping split piston rings upon a mandrel, the combination of two members movable toward and from each other and each provided with a concavity extending longitudinally thereof; a mandrel mounted within the space formed by the concavities aforesaid; a plurality of resilient pressure applying elements carried by said members aforesaid extending longitudinally thereof and likewise projecting inwardly from the wall of the concavity; and means carried by the members for retaining said resilient elements in position.

1 1. A structure as set forth in claim 13 wherein means is pro -ided for adjusting the projection of the resilient elements into the concavities. 7

In testimony whereof I have signed my name to this specification.

EMIL A. KOETI-IER. 

